In an interview with The Daily Telegraph hours after two finish-line bombs killed at least three people and injured 120, Ms Warren said she was fearful about what the attackers would "take away from us".

"The Boston marathon is always a day of great celebration, and today it was turned into tragedy," she said. "Our thoughts and prayers are with those who have been hurt, and their families.

"During the marathon we are one family. We cheer for each other, we carry each other across the finish lines. And when tragedy strikes, we are also one family. We hurt together, we help each other together".

The bombings struck on Patriot's Day, an annual public holiday in Massachusetts, on which schoolchildren and thousands of workers are given the day off for family festivities.

The 63-year-old Harvard University professor, who has represented the state in the US Senate only since January this year, hailed as heroes the runners and spectators who ran back towards the blast site to aid victims.

"People came to help, people carried each other out, with no one knowing at what risk to themselves," she said. "The people of Boston, like the marathoners, are resilient and resourceful, and we will come back from this".

Ms Warren said that President Barack Obama had contacted her to pledge every necessary resource at the federal government's disposal.

She conceded that "everyone will ask" whether more could have been done to prevent the bombings, but stressed that this was only natural after such a shocking attack.

"For now I think this is about staying focused on the priorities," she said. "The investigation has been launched to find out who did this and bring them to justice. And on that, there will be no efforts spared." Ms Warren said that after leaving the city on Monday morning, she learned of the attack after stepping off a plane at Ronald Reagan National airport in Washington, DC, and immediately feared for relatives who had run the race in past years.

"That's how everyone is," she said. "You hear about something like this and you think: 'Where are the people I know? Were they at the finish line?'" Like thousands of other Bostonians, however, the senator found that her 617-area-code mobile phone would not work, apparently due to jammed phone lines.

Finally assured that her loved ones were safe, Ms Warren returned to Boston immediately." I literally never left the airport, I stepped right back on the plane," she said. "This is family. This is family."